Several techniques for stimulation of the pelvic nerves have been developed in the past.
The sacral nerve root stimulation with sacral deafferentation, also called Brindley bladder controller, is based on the implantation of electrodes to the sacral nerve roots directly at their emergence from the spinal cord. This procedure requires a dorsal surgery with laminectomy, meaning exposure of the nerves at the back after opening the rachis. This procedure allows only en bloc stimulation of the sacral nerve roots, which means stimulation of the nerve fibers passing through the roots destined to the pelvic organs, the sphincter and the lower extremities all together and not separately. Therefore, stimulation induces at the same time bladder contraction, rectum contraction, erection and motion in the lower extremities. For control of bladder hyperactivity in spinal cord injured people, this technique required the cutting of the dorsal branches of the sacral nerves roots (sacral deafferentation) and post-stimulus effect for induction of a non-physiologic bladder voiding (bladder voiding occurs not during stimulation of the nerves but after interruption of the stimulation; early relaxation of the sphincters with further contraction of the bladder for a few seconds permits passing urine through the urethra). Therefore the stimulation must be repeated several times before the bladder is empty.
Transforaminal sacral nerve stimulation (Tanagho—U.S. Pat. No. 4,607,639, FIG. 1), is a technique wherein a multiple channel electrode is introduced by blind percutaneous puncture from the back through the sacral foramen to the sacral nerve roots. Therefore, one electrode permits stimulation of only one sacral nerve root. That means that for the stimulation of the entire nerves destined to the lower limbs and the pelvic organs and sphincters, five electrodes would be necessary (there are five sacral nerves roots per side). That is not feasible since all actual pacemakers have one or at most two channels. In this technique, stimulation cannot permit selective stimulation of the nerve fibers destined to the lower limbs, to the pelvic organs and to the sphincter—similarly to the Brindley implantation.
The perineal technique of implantation is a technique wherein an electrode is placed to the extrapelvic, that is, the perineal or infralevator portion of the pudendal nerve or its branches by perineal implantation at the space between the rectum and vagina in a female or testicles in males, the vagina or the rectum. In other words, this is an approach from below, between the legs. This technique of implantation permits selective stimulation of the pudendus nerve and its branches but permits a stimulation neither of the sciatic nerves, nor of the sacral nerves roots nor of the endopelvic portion of the pudenda nerve nor of any endopelvic nerves, because the perineum is separated from the pelvis (supralevator) by the pelvic floor.